Wave-signal translating apparatus chassis



Dec. 27, 1949 D. H MITCHELL WAVE-SIGNAL TRANSLATING APPARATUS CHASSIS 3Sheets-Sheet 1 Filed May 30, 1945 INVENTOR. DONALD H. MITCHELL E l i l LATTORNEYS Dec. 27, 1949 D. H. MITCHELL 2,492,235

WAVE-SIGNAL TRANSLATING APPARATUS CHASSIS Filed May 30, 1945 3Sheets-Sheet 2 mmmwzmc zoo n IVENTOR. DONALD H. MITCHELL ATTORNEY5 D. H.MITCHELL WAVE-SIGNAL TRANSLATING APPARATUS CHASSIS Filed May 30, 1945Dec. 27, 1949 3 Sheets-Sheet 3 04 on C5 m INVI'ZN TOR.

D ONALD H. MITCHELL WWW ATTORNEYS Patented Dec. 27, 1949 v WAVE-SIGNALTRANSLATING APPARATUS CHAS SIS Donald H. Mitchell, Chicago, Ill.,assignor to Motorola, Inc., a corporation of Illinois Application May30, 1945, Serial No. 596,783

2 Claims. (Cl. 173328) This invention relates to wave-signal translatingapparatus chassis which is substantially free from bonded circuitconnections and, while it is of general application, it is particularlysuitable for embodiment in low-cost radio broadcast re ceivers adaptedto be manufactured in large volume.-

It is well known that one of the principal cost factors of a radiobroadcast receiver is the labor cost in assembling the extremelylargenumber of circuit elements in their appropriate places and inmaking bonded connections to and between such elements, usually bysoldering. Numerous attempts have heretofore been made toward the designof a radio broadcast receiver in which all of the parts would becompletely preformed and would have connection provisions such that amere assembly of the several elements on the supporting chassis would.complete the necessary connections without requiring any permanentbonding or soldering of auxiliary connectors to complete the circuit;that is a solderless receiver substantially free from bondedconnections. However none of the arrangements so far proposed has metwith commercial success usually because of one or more of the followingfactors: (1) The fabrication process was too complicated or too costly,or both, for practical use; (2) there was no practicable way forprocuring simple circuit cross-over connections; and (3) certain of thecircuit connections were impermanent and'became noisy in operation.

It is an object of the invention, therefore, to provide a new andimproved wave-signal translating apparatus chassis substantially freefrom bonded circuit connections which is effective to overcome one ormore of the above-mentioned disadvantages and limitations on suchapparatus heretofore proposed.

It is another object of the invention to provide a new and improvedwave-signal translating ap.. paratus chassis substantially free frombonded circuit connections which is relatively simple and inexpensive tofabricate and at the same time is rugged in construction.

It is another object of the invention to provide a new and improvedwave-signal translating apparatus chassis of the type describedincorporating simple circuit cross-over provisions.

It is another object of the invention to provide a new and improvedwave-signal translating apparatus chassis of the type described in whichall of the circuit connections are permanent and are quiet in operation.

In accordance with the invention, a wavesignal translating apparatuschassis substantially free from bonded circuit connections comprises apattern sheet of insulation material having a plurality of prearrangedgroup of apertures adapted to receive plug-in devices such as vacuumtubes, circuit-element assemblies, and the like. The chassis alsoincludes a plurality of preformed circuit connectors disposed on thesheet, each including terminal elements disposed to be received incertain of the apertures of the sheet and to engage contact elements ofpredetermined ones of the devices and constituting substantially thesole connections between the devices, and means for securing theconnectors in place on the sheet.

Further in accordance with the invention, the method of fabricating awave-signal translating apparatus chassis of the type describedcomprises the step of perforating a sheet of insulation material to forma plurality of prearranged groups of apertures adapted to receiveplug-in devices, such as vacuum tubes, circuit element assemblies, andthe like. The method also includes the steps of preforming a pluralityof circuit connectors with terminal elements and constitutingsubstantially the sole connections between the devices, disposing theconnectors on the sheet with their terminal elements received in certainof the apertures thereof, and securing the connectors in placeon thesheet.

Further in accordance with the invention, in a wave-signal translatingapparatus chassis of the type described, there is provided a cross-overunit comprising a pattern sheet of insulation material, a plurality ofpreformed circuit connectors disposed on the sheet, such sheet beingformed with a non-linear aperture therein defining a tongue of suchsheet. A first of the preformed connectors has an offset portionproportioned to underlie such tongue while the second of the preformedconnectors is disposed to overlie the tongue and to extend approximatelynormal to the first connector.

Further in accordance with the invention, in a wave-signal translatingapparatus chassis of the type described there is included an arrangementfor connecting an individual circuit element to the chassis comprising apair of spaced apertures in the sheet, the apertures being disposed toregister with two predetermined connectors and the connectors includingprovisions registering with the apertures for frictionally engagingcircuit element connectors inserted therethrough.

For a better understanding of the invention, together with other andfurther objects thereof, reference is had to the following descriptiontaken accompanying drawings pointed out in the appended in connectionwith the while its scope will be claims.

Refering now to the drawings, Fig. 1 is a schematic physical layout of awave-signal translating apparatus chassis embodying the invention andutilized in a five-tube A, C.-D. C. radio broad cast receiver; Fig. 2 isa fragmentary perspective view of a portion of the chassis of Fig. lillustrating a circuit cross-over unit thereof; Fig. 3 is a detailedperspective view of an arrangement for connecting a circuit element suchas a condenser into the chassis of Fig. 1; Fig. 4 is a view in elevationof a complete radio broadcast receiver embodying the chassis of theinvention; while Fig. 5 is a schematic circuit diagram of a radiobroadcast receiver corresponding to the physical layout of Fig. 1.

Referring now to Fig. 1 of the drawings, there is represented aschematic physical layout of a wave-signal translating apparatus chassisembodying the invention and substantially free from bonded connections.Specifically, the chassis represented is that of a five-tube A. C.D. C.broadcast receiver, although it will be understood that the invention isequally applicable to chassis of other wave-signal translating apparatusor to sub-assemblies or sub-chassis thereof, and the term chassis" asused herein and in the appended claims is intended to refer to any ofsuch chassis, sub-chassis or subassembly.

The chassis of Fig. 1 comprises a pattern sheet ll of insulationmaterial, such as a thermoplastic or thermosetting resin, having aplurality of prearranged groups of apertures ll-l8, inc. Each of thesegroups of apertures is adapted to receive a plug-in device; for example,the groups II, I I, II, II and I! are adapted to receive respectively atype 12SA7 oscillator-modulator tube, a type 128K!intermediate-frequency amplifier tube, a type 12SQ7 detector and firstaudio amplifier, a type 5016 beam-power audio-frequency ampliher, and atype 3525 rectifier, while the groups I! and II are adapted to receiveintermediatefrequency selectors l9 and 20, respectively, and the groupI8 is adapted to receive the local oscillator coil assembly 2|.

The chassis also includes a plurality of preformed strip-like circuitconnectors, such as connectors 22-29, inc., comprising interconnectionsfor the plug-in devices and the connectors and II comprising the +3 andB power supply buses, respectively. There are also a group of similarpreformed connectors, such as the connectors 32-38. inc., for makingconnection between the several plug-in devices and the external circuitsof the chassis. All of the connectors 22-", inc., described are top sideof the pattern sheet ll, as viewed in Fig. 1, while there is alsoprovided a preformed connector 3.9 disposed on the opposite side of thepattern sheet Ill and constituting the ground or reference potential busof the chassis.

As shown more clearly in Fig. 2, each of the connectors, such asconnectors I0 and II. includes one or more terminal elements. such asthe terminal elements Ina and Ila, disposed to be received in certain ofthe apertures of the pattern sheet l0: in the case of the terminalelements Illa and Ila, to engage two of the apertures of the group I8into which the oscillator coil assembly is to be plugged. As shown inFig. 2, each of the terminal elements Illa, Ila comprises an elongatedresilient contact clip exinc., and the condensers tending from itsrespective preformed connector and through its respective aperture inthe pattern sheet ill. Preferably, the preformed connectors of the typedescribed constitute substantially the sole connections or the entireconnections between the several plug-in devices, such as the vacuumtubes described and the plug-in units is, 20 and ii, and to all externalcircuits to the chassis.

The chassis of Fig. 1 also includes a plurality of circuit cross-overunits or arrangements for the connectors. These may be identified as thecircuit cross-overs I2I8a, inc. Each of these cross-over units may beeither single or double, by way of example the double cross-over I2being represented in detail in Fig. 2. As shown in this figure, thecross-over I2 comprises a U-shaped aperture I2a punched or otherwiseformed in the pattern sheet Hi and a first preformed connector, forexample the B bus 3|, having an oiiset portion lla proportioned anddisposed to underlie the tongue I2b between the arms of the U-shapedaperture In. The cross-over connectors In and II are disposed to overliethe tongue I2b and to extend approximately parallel thereto andapproximately normal to the connector II. In this fashion, it is seenthat the cross-over connectors II, It and II are completely insulatedfrom each other and at the same time permanently retained out of contactwith each other.

The chassis of Fig. 1 also includes a plurality of arrangements forconnecting individual circuit elements to the chassis, such as resistorsRi-Ra. C1-C1, inc. For example, one such arrangement is shown in Fig. 3illustrating the connection of the condenser C1 to the preformedconnectors II and II. As illustrated in Fig. 3, the pattern sheet III isprovided with a pair of llb, respectively, of the condenser Ca. Forexample, the connector II is formed with a small diamond-shaped aperture3Ia having a pair of opposed peripheral fingers lIb. The connectorelements are preferably of resilient material such as Phosphor bronzeand the fingers, such as the fingers III), are offset from the plane ofthe connector so that they resiliently grip the circuit elementconnector 50b inserted through the apertures Ma and Ilb. Thisarrangement for connecting individual circuit elements merely byinserting or plugging them into appropriately spaced apertures in theseveral connectors is the manner of connection of the resistors R1-Ra,inc., and the condensers are It has been found that, with theconstruction illustrated, a permanent and quiet electrical connection isestablished between the circuit element connectors, such as theconnectors "a, "b of condenser Ca, and the preformed chassis connectorsand that this engagement is sufficiently strong that if it is attemptedto remove the circuit elements, such as the condenser C1, the connectors"a, no may be torn from the circuit element or broken or, in some cases,the connection with the preformed chassis connectors permanentlydeformed.

The chassis of Fig. 1 also incorporates means for securing the severalpreformed circuit connectors 22-38, inc., in place on the pattern sheetC1-C1, inc., and the resistors R1-Rs, inc.

ner. The-sheets II and II are. secured together by screws, bolts,rivets, or the like, not shown.

The chassis of Fig. 1 is also adapted tobe connected to other elementsof a radio broadcast receiver not forming a part of .the chassis per se.For example, the circuit connectors 32 and 34 are provided withterminals 32a and Ne, respectively, adapted to be connected to anexternal loop or antenna ground circuit. Similarly, the connectors 31and II are provided with terminals 31a and Ila, respectively, which areadapted to be bridged by the back cover of the receiver carrying theloop, as described hereinafter, in order to open the power circuit tothe chassis when the cover is removed and the various circuit elementsof high potential are exposed. Further there is provided a separatevolume control unit 82 having a conventional flexible connector no tothe B bus ll. Also the receiver includes a sound reproducer or loudspeaker I having an operating mechanism a which is connected topreformed connectors 54 and I8 constituting additional ground connectorsand disposed on the opposite side of the pattern sheet 5| The speakeroperating mechanism 53a is also provided with an external connectionplug 53b having the connection prongs indicated as SP, 8+8 and SFandadapted to be connected to a conventional socket 530 havingconnections to points correspondingly identified on the chassis. Thereceiver is also provided with an electrolytic filter condenser Csconnected by conventional leads 56, 51 and 58 to the circuit connectors16,

30 and 3|, respectively. Power for the receiver chassis is derived froman ordinary commercial power circuit by means of a removable plug 59having leads 5! and Si connected to the bus connector 3| and to theconnector 38, respectively.

In the fabrication of the wave-signal translating apparatus chassis ofFig. 1 described above, the pattern sheet iii of insulation material isperforated with registering groups of apertures ll-ll, inc., for theplug-in vacuum tubes and selector and oscillator-coil assemblies andwith a plurality of pairs-of spaced apertures, such as the apertures49a, 49b, for receiving the indi vidual circuit elements such as thecondensers The sheet Si is also perforated with groups and pairs ofapertures registering with those of pattern sheet it, one such apertureSla being shown in Fig. 3. The pattern sheet It is also punched orstamped to provide a plurality of U-shaped apertures, such as theaperture 42a, to permit the formation of the cross-over units 424, inc.

The chassis circuit connectors, such as the connectors 2248, inc., arethen stamped or otherwise formed from strip or sheet material,preferably of a resilient spring metal such as Phosphor bronze. Portionsof the preformed connectors are formed into elongated resilient contactclips, such as the clips a, tin of Fig. 2, extending therefromsubstantially normal to the plane of groups of apertures "-48, inc. Inpredetermined .6 to engage appropriateones ofthe ones cfztbe ,chcuitconnectors 21-", inc., to

which individill circuit elements are to be attached, there are formedin pairs provisions for frictionally engaging the individual circuitelement connectors when inserted through the pairs of apertures formedin the sheets ll andliregistering therewith. The frictional engagingprovisions may be of the form illustrated in Fig. 3 and described.above. Theconnectors I240, inc., are thereupon disposed on one side ofthe pattern sheet II with their terminal elements or clips, such as theclips or, a, received in and extending through theircorrespondingapertures inthe sheet II. The preformed ground connector II is disposedon the opposite side of the pattern sheet .IO and secured thereto in anysuitable fashion while the ground connectors l4 and. II are disposed onthe inner side of the sheet II and secured thereto.

Each of the U-shaped apertures, such as the apertures "a, is located atone of the circuit cross-over points of two of the preformed connectors22-, inc., to form the cross-over units 4248a, inc. To this end, such ofthe circuit connectors as are involved in the circuit cross-over have aportion thereof offset, such as the offset portion Ila (Fig. 2) ofconnector fl, to underlie the tongue of the associated aperture in thesheet II, while the crossing connector or connectors are disposed andarranged to overlie the tongue and extend approximately normal to theunderlying connector.

Thereupon the several connectors are secured in place. This may beeflfected in any convenient manner but preferably and as illustrated byjuxtaposing the pattern sheet ii upon the pattern sheet it with theirapertures in register and securing them together by any suitable meanssuch as screws, rivets, or the like, (not shown) to retain the circuitconnectors in place.

In Fig. 4 is illustrated a view in elevation, partly in section, of acomplete radio broadcast receiver incorporating the chassis apparatus ofthe invention. This receiver comprises an enclosing cabinet or housingill with the chassis comprising the pattern sheets i0 and Si mountedvertically therein and extending substantially across the inside of thecabinet. The various vacuum tubes, such as the tube 8i, and the variouscoil assemblies, such as the oscillator assembly 2|, are plugged in tothe chassis of the set and extend horizontally therefrom. Also securedto the chassis by screws, bolts, rivets, or the like, is the volumecontrol unit 52 provided with a manually operable adjusting knob 52amounted on a shaft 52b extending through the front of the cabinet. Theloud speaker 53 is also secured to the chassis sheets and SI by means ofscrews or bolts "b which also engage the ground or reference potentialbuses 54, it, thereby grounding the unit. The tuning condensers arelikewise secured to and supported from the chassis sheets l0 and ii andare provided with a tuning knob 62 secured to a shaft 82a extendingthrough the front of the cabinet and connected to adjust the tuningcondensers through gearing 2b. The back of the cabinet It is closed by apanel member ll spaced from the chassis sheets l0 and Si by suitableposts It having pins "a engaging the terminal contacts 32a and "a. Areceiving loop antenna 05 is mounted on the back plate It, while thisplate also carries a the connectors and at predetermined spaced 1bridging contact (not shown) for the power supnon-linear slot thereinof, a first one 01' said --set portion 01 such a,saa,ass

is an entirely conventional five-tube A (1-D. C. I

superheterodyne receiver, the operation of is well understood in theart, it is believed that an explanation of such operation is unnecessaryherein. While the invention has been illustrated and described asapplied to a conventional fivetube A. (1-D. C. superheterodvne-broadcastreceiver, it is to be understood that this embodiment is purelyillustrative and that the chassis oi the invention is applicablegenerally to chassis of wave-signal translating apparatus, includingreceivers and transmitters, comprising either the complete chassis ofthe wave-signal translating apparatus or a sub-chassis or sub-assemblythereof.

While there has been described what is at present considered to be thepreferred embodiment of the invention, it will be apparent to thoseskilled in the art that various changes and modifications may be madetherein without departing from the spirit or scope of the invention.

What is claimed as new is:

1. A chassis for supporting and interconnecting electrical devices oithe plug-in type, said chassis comprising a fiat sheet of insulatingwhich material having apertures arranged to conform with a predeterminedpattern for receiving the plug portions of the electrical devices, aplurality of rigid strip conductors respectively extending betweenpredetermined ones of said apertures, and holding means for securingsaid conductors to said insulating sheet, said conductors havingintegral spring contact clips respectively positioned in certain of saidapertures in said sheet for directly receiving the plug portions andatiording unbonded electrical connections therewith, said insulatingsheet having at least one defining a tongue thereconductors having an01!- configuration to be transversely lnsertable in said slot tounderlie said tongue, another one 01 said conductors being disposed tooverlie said tongue and extend approximately normal to said firstconductor, whereby said tongue extends between such conductors toinsulate them one from the other, said spring contact clips and saidoffset portion or said conlog electrical devices first insulating slotsaid insulating sheet. 7

2. A chassis for supporting and interconnectci. the plug-in ype. saidchassis comprising a first fiat sheet of insulating material havingapertures arranged to conform with a predetermined pattern for receivingthe plug portions or all said devices, a plurality of rigid stripconductors respectively extending between predetermined ones of saidapertures, and a second insulating sheet secured to the first insulatingsheet with said conductors of such configuration to be transverselyinsertable in said slots to underlie said tongues. said spring contactclips and said ofiset portions of sheet, being respectively disposed tooverlie said tongues to provide insulated cross-overs between saidconductors.

DONALD E. CHELL.

REFERENCES CITED The following references are of record in the file ofthis patent:

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